Some individuals suffer debilitating podiatric conditions and require the fabrication of prescription orthotics by a medical doctor for remedial relief. However, many of the problems commonly experienced with articles of footwear by a large segment of the general public simply stem from inadequate conformance or fit, stability, support and comfort. Further, it can be readily understood that at least one of these problems can be related to the additional need or desire to attenuate force applications and resulting shock experienced by a wearer of footwear. Eversion of the foot is commonly referred to as pronation, whereas inversion of the foot is commonly referred to as supination. It is the aim of several preferred embodiments of the present invention to provide support and stability to the wearer's foot so that injurious conditions possibly arising from excessive pronation or supination can be mitigated, or avoided. Every individual has different anatomical features and characteristics. A practical problem to be solved: How to accommodate for individual differences and provide substantial conformance or fit, stability, support, comfort, and/or attenuate force applications and shock experienced by a user of articles of footwear?
Heretofore, there have been a number of attempted solutions to this problem which have enjoyed varied success. Obvious merits aside, some of the deficiencies of the prior art will be briefly addressed. For example, footwear orthotics prescribed by a medical doctor are sometimes required in select cases to remedy debilitating podiatric conditions. For some individuals, there is no other practical or prudent alternative which will provide remedial relief. However, footwear orthotics often take considerable time for a specialist to fabricate and can be relatively expensive. Prescription orthotics are not normally required for the general public to successfully enjoy the use of footwear.
Various thermally formable footwear devices have been introduced in the United States market and have enjoyed some commerical success. In particular, skate and ski boot manufacturers have made numerous attempts in this regard. However, the application of a thermally formable footwear device generally entails the use of a heating gun, or oven, or other heating and/or molding equipment and involves numerous procedures which must be administered by a retailer. While less expensive, such devices suffer many of the deficiencies of the prior art described herein.
Pre-formed "generic" products can accommodate a greater, or lesser number of individuals depending upon the degree to which characteristic norms corresponding to the user population have been incorporated in the design of such products. In particular, foam materials of select shape have been used to partially accomodate for anatomical differences and enhance the conforming properties of articles of footwear. However, as every individual possesses different anatomical features and characteristics, a pre-formed "generic" product will not accommodate every individual to the same degree.
Permanently inflated air bags, or "diffusion pumping devices" such as those taught by Marion F. Rudy, (e.g., U.S. Pat. Nos. 3,760,056, 4,183,156, and 4,340,626), and the like, have enjoyed considerable commerical success, and have enhanced the cushioning and shock-absorbing qualities of articles of footwear. However, the use of relatively high inflation pressures in permanently inflated air bags, and the like, generally achieves superior cushioning and shock-absorption at the expense of conformance, whereas relatively low inflation pressures achieve conformance at the expense of cushioning and shock-absorption.
Selectively inflatable air devices, e.g., those which can be manually actuated by a pumping mechanism, can attain substantial conformance with respect to a portion of a wearer's anatomy. However, the relatively low inflation pressures commonly associated with such devices do not provide for substantial cushioning, shock-absorption, or stability when such devices are subjected to the force applications commonly encountered by a wearer during the use of an article of footwear.
There have been a number of attempts to introduce conformable materials in a liquid or viscous state into articles of footwear in order to customize the article of footwear for an individual user. These materials remain in a liquid, or viscous state and when subjected to a force application and/or body heat become moldable in conformance with a portion of the wearer's anatomy. However, such materials and devices normally resume an unformed state upon removal of an article of footwear and are therefore without a "memory" capability. In addition, such materials can add undesirable weight to an article of footwear when used in substantial quantities.
In addition, there have been attempts to introduce conformable materials in a fluid state into an article of footwear which can be made to form a resilient material, e.g., substantially comprising an elastomeric resilient material consisting of solid matter, after a working time. Some of the prior art has proven deficient by virtue of inadequate design, or materials. Moreover, the procedures and methods associated with these attempts have for the most part been relatively complex, time consuming, expensive, or otherwise not amenable to mass production and use by the general public.
Lastly, a deficiency common to much of the prior art discussed above is the inability to exhibit select and varied mechanical or other physical properties as between select areas of a prior art footwear device. Most prior art devices are relatively homogenous with regards to their mechanical and other physical properties. Few prior art devices have the ability to be "tuned" to exhibit various desired mechanical or other physical properties in various select portions.
Accordingly, special attention is merited by a number of practical problems which are encountered when a preferred conformable material in a substantially fluid state, (e.g., a liquid, and/or viscous material which can be made to form an elastomeric resilient material substantially comprising solid matter after a working time), is used within a prior art reference, or a conformable cushioning and stability device of the present invention, hereafter simply referenced as a "conformable device." One problem arises out of the need or desire to limit the quantity and/or the weight by volume of the conformable material to be used within a conformable device. A second problem arises out of the need or desire to selectively vary the mechanical or other physical properties exhibited in select areas of a conformable device and thereby "tune" the mechanical or other physical properties exhibited in various portions of a conformable device. In any given application, a third problem arises out of the need or desire to accomodate the anatomical variation found in a large percentage of the user population with relatively few alternate embodiments of a conformable device. For example, different users will often displace different quantities of conformable material in attaining a desired condition when using the present invention. The present invention provides solutions to these and other problems.